This sets of MCQ's contains objective on turbo machines with answers for preparation of your exams in part 6....
SET 1 of turbo machines mcqs
1. Value of Cofficient of velocity Cv for nozzle in pelton wheel lies between
A : 0.85 to 0.9
B : 0.9 to 0.95
C : 0.95 to 0.97
D : 0.97 to 0.99
Answer:-D : 0.97 to 0.99
Q.no 2. A reaction turbine works under a head of 68 m. Assuming flow ratio as 0.15, find vlocity of flow.
A : 5.47 m/s
B : 2.4 m/s
C : 2.02 m/s
D : 13.4 m/s
Answer:-A : 5.47 m/s
Q.no 3. The hydraulic efficiency of an impulse turbine is maximum when velocity of wheel is _______ of the jet velocity,
A : One-fourth
B : One-half
C : Three-fourth
D : Double
Answer:-B : One-half
Q.no 4. A Pelton wheel is ideally suited for
A : high head and low discharge
B : high head and high discharge
C : low head and low discharge
D : medium head and medium discharge
Answer:-A : high head and low discharge
Q.no 5. A jet after striking a smooth plate comes out with a __________ velocity.
A : Increased
B : Decreased
C : Same
D : Zero
Answer:-C : Same
Q.no 6. Power supplied to the kaplan turbine is 1830 kW which developes power 1500 kW. Find Hydraulic efficiency of the turbine.
A : 81.96%
B : 19.67%
C : 18.85%
D : 96.38%
Answer:-A : 81.96%
Q.no 7. Power supplied to francis turbine is 15000 kW and having hydraulic efficiency of the turbine 94 % Find the power developed to the turbine.
A : 14100 kW
B : 6204 kW
C : 3948 kW
D : 28764 kW
Answer:-A : 14100 kW
Q.no 8. The maximum hydraulic efficiency of an impulse turbine is (where φ = Angle of blade tip at outlet)
A : (1+Cos F)/2
B : (1-Cos F)/2
C : (1+Sin F)/2
D : (1-Sin F)/2
Answer:-A : (1+Cos F)/2
Q.no 9. In a velocity triangle at outlet, if angle β >90 degrees , then direction of Vw1 and Vw2 are________ _________
A : Same
B : Opposite
C : Perpendicular to each other
D : Parallel to each other
Answer:-A : Same
Q.no 10. Jet of water strikes a stationary plate. Workdone by the jet will be
A : Negative
B : Positive
C : Zero
D : Unpredictable
Answer:-C : Zero
SET 2 of turbo machines mcqs
Q.no 11. A pelton wheel operates with a speed of 600 RPM speed ratio of 0.44 and net head of 300 m diameter of the wheel is
A : 0.82 m
B : 1.07 m
C : 1.51 m
D : 2.14 m
Answer:-B : 1.07 m
Q.no 52. The theoretical maximum efficiency of a pelton turbine is
A : 1/2( 1+ cos φ)
B : 1/2( 1+ cos2 φ)
C : 1/2( 1- cos φ)
D : 1/2( 1+ cos φ/2)
Answer:-A : 1/2( 1+ cos φ)
Q.no 13. The ratio of actual work available at the turbine to the energy imparted to the wheel is known as ________ efficiency.
A : Hydraulic
B : Mechanical
C : Overall
D : None of these
Answer:-B : Mechanical
Q.no 14. The speed factor in a turbine represent the ratio between
A : peripheral velocity of vane and spouting velocity
B : whirl velocity and peripheral velocity
C : flow velocity and spouting velocity
D : absolute velocity and supporting velocity
Answer:-A : peripheral velocity of vane and spouting velocity
Q.no 15. A Pelton wheel develops 1750 kW under a head of 100 meters while running at 200 r.p.m. and discharging 2500 liters of water per second. The unit discharge of wheel is
A : 0.25 m3/s
B : 0.5 m3/s
C : 1.5 m3/s
D : 2.5 m3/s
Answer:-A : 0.25 m3/s0
Q.no 16. Power supplied to francis turbine is 200 kW and having overall efficiency of the turbine 75 % Find the power developed to the turbine.
A : 69 kW
B : 244.5 kW
C : 150 kW
D : 55.5 kW
Answer:-C : 150 kW
Q.no 17. A horizontal water jet with a velocity of 10m/s and cross sectional area of 10 mm2 strikes a flat plate held normal to the flow direction.The density of water is 1000 Kg/m3.The total force on the plate due to the jet is
A : 100N
B : 10N
C : 1N
D : 0.1N
Answer:-C : 1N
Q.no 18. Number of buckets in Pelton wheel is given by Z= 15 + 0.5 m, this equation is called as Tygun formula
A : TRUE
B : FALSE
C : Not Applicable
D : Data Missing
Answer:-A : TRUE
Q.no 19. A series of vanes are mounted on a wheel which turns when a fluid Jet impinges on to the vane. Maximum efficiency will occur when the wheel peripheral speed equal's ______ the jet velocity.
A : one-third
B : one -half
C : two - third
D : four-fifth
Answer:-B : one -half
Q.no 20. In the Equation, u= πDN/60, D is
A : Diameter of runner
B : Mean Diameter of runner
C : Diameter of Nozzle
D : Diameter of Jet
Answer:-B : Mean Diameter of runner
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